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Background: Infectious diseases and social contacts in early life have been proposed to modulate brain tumour risk during late childhood and adolescence.Methods: CEFALO is an interview-based case-control study in Denmark, Norway, Sweden and Switzerland, including children and adolescents aged 7-19 years with primary intracranial brain tumours diagnosed between 2004 and 2008 and matched population controls.Results: The study included 352 cases (participation rate: 83%) and 646 controls (71%). There was no association with various measures of social contacts: daycare attendance, number of childhours at daycare, attending baby groups, birth order or living with other children. Cases of glioma and embryonal tumours had more frequent sick days with infections in the first 6 years of life compared with controls. In 7-19 year olds with 4+ monthly sick day, the respective odds ratios were 2.93 (95% confidence interval: 1.57-5.50) and 4.21 (95% confidence interval: 1.24-14.30).Interpretation: There was little support for the hypothesis that social contacts influence childhood and adolescent brain tumour risk. The association between reported sick days due to infections and risk of glioma and embryonal tumour may reflect involvement of immune functions, recall bias or inverse causality and deserve further attention. [ABSTRACT FROM AUTHOR]

There is public concern that use of mobile phones could increase the risk of brain tumours. If such an effect exists, acoustic neuroma would be of particular concern because of the proximity of the acoustic nerve to the handset. We conducted, to a shared protocol, six population-based case-control studies in four Nordic countries and the UK to assess the risk of acoustic neuroma in relation to mobile phone use. Data were collected by personal interview from 678 cases of acoustic neuroma and 3553 controls. The risk of acoustic neuroma in relation to regular mobile phone use in the pooled data set was not raised (odds ratio (OR) = 0.9, 95% confidence interval (CI): 0.7-1.1). There was no association of risk with duration of use, lifetime cumulative hours of use or number of calls, for phone use overall or for analogue or digital phones separately. Risk of a tumour on the same side of the head as reported phone use was raised for use for 10 years or longer (OR = 1.8, 95% CI: 1.1-3.1). The study suggests that there is no substantial risk of acoustic neuroma in the first decade after starting mobile phone use. However, an increase in risk after longer term use or after a longer lag period could not be ruled out. [ABSTRACT FROM AUTHOR]

Objective: The aim of this nested case-control study was to test the hypothesis that exposure to electromagnetic fields from high-voltage power lines increases the incidence of hematological cancers in adults. Data from an occupational exposure matrix was also used.Methods: The study population comprised subjects aged 16 and above who had lived in a residence situated in a broad corridor around a high-voltage power line in 1980, or one of the years from 1986 to 1996. The cases were incident cases diagnosed 1980-1996. Two controls were matched to each case by year of birth, sex, municipality and first year entering the cohort. Time-weighted average exposure to residential magnetic fields generated by the power lines was calculated for the exposure follow-up from January 1, 1967 until diagnosis using cut-off points at 0.05 and 0.20 microT. In addition, job titles and industrial branch was classified as categories of hours per week in a magnetic field above background (0.1 microT). Subjects exposures were cumulated over occupationally active years for the exposure follow-up January 1, 1955 until diagnosis.Results: When residential magnetic fields are evaluated, the two upper residential time weighted average magnetic field categories showed non-significant elevated odds ratios (ORs) for all leukemia combined (OR: 1.3, 95% confidence interval (CI) 0.7-2.5 and OR: 1.5, 95% CI: 0.8-3.0). The increased risk was confined to chronic lymphocytic leukemia, acute lymphocytic and acute myeloid leukemia. Lymphoma showed a non-significant lower OR in the upper exposure category. Multiple myeloma showed non-significant elevated ORs. Occupational exposure showed no significant association to exposure for any site.Conclusions: Some elevated ORs were observed in the present study, but the results are based on small numbers and no firm conclusions can be drawn. [ABSTRACT FROM AUTHOR]

Previous studies have suggested an association between exposure to 50-60 Hz magnetic fields (EMF) and childhood leukaemia. We conducted a pooled analysis based on individual records from nine studies, including the most recent ones. Studies with 24/48-hour magnetic field measurements or calculated magnetic fields were included. We specified which data analyses we planned to do and how to do them before we commenced the work. The use of individual records allowed us to use the same exposure definitions, and the large numbers of subjects enabled more precise estimation of risks at high exposure levels. For the 3203 children with leukaemia and 10 338 control children with estimated residential magnetic field exposures levels < 0.4 μT, we observed risk estimates near the no effect level, while for the 44 children with leukaemia and 62 control children with estimated residential magnetic field exposures ≥ 0.4 μT the estimated summary relative risk was 2.00 (1.27-3.13), P value = 0.002). Adjustment for potential confounding variables did not appreciably change the results. For North American subjects whose residences were in the highest wire code category, the estimated summary relative risk was 1.24 (0.82-1.87). Thus, we found no evidence in the combined data for the existence of the so-called wire-code paradox. In summary, the 99.2% of children residing in homes with exposure levels < 0.4 μT had estimates compatible with no increased risk, while the 0.8% of children with exposures ≥ 0.4 μT had a relative risk estimate of approximately 2, which is unlikely to be due to random variability. The explanation for the elevated risk is unknown, but selection bias may have accounted for some of the increase. [ABSTRACT FROM AUTHOR]

Experimental studies suggest that melatonin has a protective effect against breast cancer. Exposure to light suppresses melatonin secretion, but to a lesser degree in totally blind persons. Breast cancer was investigated in a cohort of 15 412 Norwegian visually impaired women. The risk among totally blind women was 0.64 (95% CI = 0.21-1.49, 5 cases only), and for those who became blind before age of 65, the SIR was 0.51 (95% CI = 0.11-1.49). Our findings give support to the 'melatonin hypothesis'. [ABSTRACT FROM AUTHOR]

A letter to the editor is presented in response to the article "Mobile phone use and acoustic neuroma in five North European countries."